Wes and Robin, I only know of Ross as a dealer and teacher of concertinas but my grandfather, Henry Thomas Crabb does seem to have made concertinas for Ross during the period 1927 – 1929. From the records it seems that all instruments supplied were of English system and included various models i.e. 48 key Hexagonal Mahogany Trebles ‘The £5 model’, 48 key Hexagonal Metal topped Trebles, 48 key Octagonal Amboyna Trebles, 48 key Hexagonal Metal topped Trebles, 48 key Octagonal Amboyna Tenors